Shoulder impingement has been identified as the most common cause of shoulder pain in the adult general population. High-Velocity, Low-Amplitude Thrust Manipulations (HVLATM) of the thoracic spine and ribs result in increased shoulder ROM, as well as decreased pain and disability in patients suffering shoulder impingement. The quality of the sparse publications is low and lacking control or comparison groups regarding the use of HVLATM in the management of shoulder impingement. Further higher quality randomized clinical trials are needed. Moreover, no research has investigated the effects of the patients beliefs and different types of verbal messages conveyed by the clinician to the subjects in regard to the effects of HVLATM of the thoracic spine on shoulder pain and function. The purpose of this study is to evaluate, in subjects with signs and symptoms of shoulder impingement: (1) the effects of a series of the prone thoracic spine High Velocity Low Amplitude Thrust Manipulation (HVLATM) as compared to the HVLATM directed at the scapula, on shoulder pain, impingement symptoms, and functional outcomes; (2) the effect of the type of message and language used by the clinician in regard to thoracic HVLATM on shoulder pain, impingement symptoms, and functional outcomes; (3) the effect of subject's expectation of outcome of thoracic and scapula HVLATM on shoulder pain, impingement symptoms, and functional outcomes; (4) if these potential immediate improvements will be sustained at 6 to 9-day follow up.